Rigid shock-resistant vinyl halide polymer compositions and method of making same

ABSTRACT

A thermoplastic composition comprises an intimate mixture of (1) a rigid vinyl halide polymer or a rigid polymer of a monomer mixture comprised predominantly of a vinyl halide and lesser amounts of other mono-olefinic monomers; (2) a hard, tough, resinous polymer of a mixture comprising 50 to 90 weight per cent of a styrene and 10 to 50 weight per cent of an acrylonitrile copolymerizable with the styrene monomer and (3) a rubbery interpolymer of a monomer mixture comprising 50 to 90 weight per cent of a 1,3-butadiene hydrocarbon, 5 to 30 weight per cent of an acrylonitrile and 5 to 30 weight per cent of at least one other monoolefinic monomer copolymerizable with the 1,3-butadiene hydrocarbon and an acrylonitrile, the composition containing essentially from 1 to 40 weight parts of (2) based on 100 weight parts of (1) and 1 to 25 weight parts of (3) based on 100 weight parts of (1) and (2).  The polymer (1) may be polyvinyl chloride, fluoride, or bromide or a copolymer of vinyl chloride, fluoride or bromide with vinylidene chloride, vinyl acetate, butyrate or benzoate, acrylic or ethacrylic acid, ethyl or octyl acrylate, methyl methacrylate, butyl ethacrylate, acrylamide, acrylonitrile, styrene, chlorostyrene, ethyl styrene, vinyl naphthalene, diethyl maleate, vinyl pyridine or isobutylene.  The polymer (2) may be a copolymer of styrene, methyl or ethyl styrene or monochloro- or dichlorostyrene and acrylonitrile, methacrylonitrile, ethacrylonitrile or chloroacrylonitrile.  The rubbery interpolymer (3) may be an interpolymer of 1,3-butadiene or isoprene, acrylonitrile or chloroacrylonitrile and one or more of styrene, dichlorostyrene, ethyl, butyl and hexyl acrylate, methyl, butyl and octyl methacrylate, vinyl methyl ketone, vinyl ethyl ether, vinyl pyridine and vinyl naphthalene.  The composition may be made by mixing the polymers as dry powders, in solution or as aqueous dispersions.  Specification 705,021 is referred to.

Patented Oct. 1, 1957 RIGID SHOCK-RESISTANT VINYL HALIDE POLYMERCOMPOSITIONS AND METHOD OF MAKING SAME Clarence E. Parks, Bay Village,and George L. Wheelock,

Akron, Ohio, assignors to The B. F. Goodrich 6Company, New York, N. Y.,a corporation of New York No Drawing. Application May 6, 1953, SerialNo. 353,446

10 Claims. (Cl. 260--45.5)

This invention relates to thermoplastic vinyl halide polymercompositions which possess excellent physical properties including highimpact strength and shock resistance, and it relates particularly tohard, tough, rigid, but processable compositions comprising an intimatemixture of a vinyl halide polymer, a polymeric resinous processing aidcompatible therewith, and a rubbery interpolymer.

In the copending application of Garland B. Jennings, Serial No. 2ll,984,filed February 20, 1951, now U. S. Patent 2,646,417, there is discloseda new class of hard and rigid thermoplastic compositions which may bereadily processed by conventional plastic processing techniques withoutadded plasticizer. These compositions are blends of a vinyl halidepolymer, such as polyvinyl chloride, with a hard resinous copolymer ofstyrene and acrylonitrile. These compositions, while they are tough andhard, are not as shock-resistant as is sometimes desirable in a hard,rigid, plastic composition or product. The use of certain rubberymaterials in thermosetting resins, such as phenol-formaldehyde, toimprove shock resistance, is well known; but when the rubbery materialsordinarily employed in such applications are mixed with theabove-identified rigid, vinyl thermoplastic compositions, very inferiorproducts are obtained. The processing characteristics of such acomposition are poor, tack is increased, and the physical properties ofthe product in general are greatly harmed. For example, tensilestrength, flexural strength, heat distortion point and the like aredecreased to such a degree that useful products are not obtained.

It has been found that rigid, hard, tough vinyl halide polymercompositions may be prepared which have extremely high impact resistanceand at the same time retain good processing characteristics, as well asthe many advantages and good physical properties of an unplasticizedhalide polymer composition. These improved compositions are intimatemixtures of the vinyl halide polymer, a polymeric resinous polymercompatible therewith, such as a styreneacrylonitrile copolymer resin,and a rubbery interpolymer of a bntadiene-l,3 hydrocarbon, anacrylonitrile and at least one other copolymerizable monoolefinicmonomer. When these polymeric ingredients are intimately mixed, as willbe hereinafter described, the rigid composition resulting is unusuallyand surprisingly shock-resistant, is readily processable and, quiteunexpectedly, retains essentially all of the desirable properties of theoriginal vinyl halide polymer virtually unimpaired and in good balance.The copending application of Clarence E. Parks and Garland B. Jennings,Serial No. 353,452, filed May 6, 1953, discloses that the addition of apolyvalent metal compound to this composition further increases theshock resistance of these compositions.

In accordance with this invention typical thermoplastic compositions areprepared, for example, by intimately blending, as by mastication andheat, about 100 weight parts of a vinyl halide polymer, such aspolyvinyl chloride, with about 10 weight parts of a resinousstyreneacrylonitrile copolymer, and about 10 weight parts of a rubberyinterpolymer of 1,3-butadiene, acrylonitrile and styrene. The resultingcomposition has a tensile strength of about 5800 pounds per square inch,21 flexural strength of about 11,000 pounds per square inch and an Izodimpact value of about 9.5. The Izod impact value of a similar mixture ofpolyvinyl chloride with a styreneacrylonitrile copolymer is only about0.5. The compositions of this invention have excellent processingcharacteristics, and they may be extruded, calendered, molded, drawn,embossed, machined and otherwise treated to form useful rigidshock-resistant products and articles which have an excellent balance ofgood chemical, physical and electrical properties.

The vinyl halide polymers which are utilized in preparing thecompositions of this invention include all of the normally rigid, hard,tough polymeric materials comprised predominantly of polymerized vinylhalide, that is, homopolymers of the vinyl halides such as polyvinylchloride, polyvinyl fluoride and polyvinyl bromide, as Well ascopolymers containing greater than 50 percent of bound vinyl halide andlesser amounts of other monoolefinic monomers. Multicomponentinterpolymers made from monomer mixtures containing predominantly avinyl halide monomer and minor amounts of one or more othercopolymerizable monoolefinic monomers may also be employed so long asthey are normally rigid copolymers. Such other copolymerizablemonoolefinic monomers which may be interpolymerized with the vinylhalides include vinylidene halides such as vinylidene chloride; vinylesters such as vinyl acetate, vinyl butyrate, vinyl benzoate and thelike; acrylic and alpha-alkyl acrylic acids, their alkyl esters, amidesand nitriles such as acrylic acid, ethacrylic acid, ethyl acrylatc,octyl acrylate, methyl methacrylate, butyl ethacrylate, acrylamide,acrylonitrile and the like; vinyl aromatic compounds such as thestyrenes including styrene, chlorostyrene, ethyl styrene and the like;vinyl naphthalene; alkyl esters of maleic and fumaric acid such asdiethyl maleate; vinyl alkyl ethers and vinyl alkyl ketones; vinylpyridine; isobutylene and various other coploymerizable monoolefinicmonomers; especially those containing the CH2=C group. The vinyl halidepolymer preferably employed is polyvinyl chloride or vinyl chloridecopolymers which contain only minor proportions of other copolymerizedmonoolefinic monomers such as copolymers of 50, and preferably 70 to 99percent of vinyl chloride and, for example, about 1 to 30 percent ofvinylidene chloride, vinyl esters and acrylic acid esters; ormulti-component interpolymers such as those, for example, containingabout 70 to percent vinyl chloride, 5 to 25 percent vinylidene chloride,and 5 to 25 percent vinyl esters such as vinyl acetate, vinyl benzoate,and alkyl acrylates or alkyl methacrylates. Regardless of the particularcomonomers employed, the end products of this invention are preferablyobtained by employing a normally rigid vinyl halide polymer.

The vinyl halide polymers may be prepared by any of the polymerizationtechniques known to and employed by those skilled in the art. Suchmethods as solution, suspension, emulsion and the like are preferred.The polyvinyl chloride preferred for this use is preferably a hard,tough, high-molecular weight material of uniform molecular weightdistribtuion and particle size, so as to take advantage of all of theexcellent properties inherent in this material. The form of the vinylhalide polymer may be the solid dried product in powder or granularform; or as a suspension, solution or emulsion, as will be more fullydescribed hereinafter.

The polymeric resinous processing aids employed to prepare thecompositions of this invention are preferably styrene-acrylonitrilepolymers which are compatible with the vinyl halide polymer. Theseresins are prepared by polymerizing a monomeric mixture consistingessentially of a styrene and an acrylonitrile. Such mixtures may alsocontain minor amounts of other copolymerizable monoolefinic monomers ofthe type hereinbefore described as minor constituents. The styreneutilized is preferably styrene itself. Other useful styrenes includealkyl styrenes such as methyl styrene, ethyl styrene; halo styrenes suchas chlorostyrenes represented by monochlorostyrene and dichlorostyrenes;alkoxy styrenes and like styrene derivatives copolymerizable withacrylonitrile. Better results are obtained if the resin contains greaterthan 50 percent of bound styrene or is prepared from monomer mixturescontaining greater than 50 weight percent of styrene. The acrylonitrilecomonomer em ployed in the monomer mixture is preferably acrylonitrile.Other useful acrylonitriles include alkyl acrylonitriles such asmethacrylonitrile and ethacrylonitrile, chloroacrylonitrile and thelike, in amounts from to 50 percent in the monomer mixture and resultingcopolymer. The other minor monoolefinic constituents, if employed, arepreferably less than percent. It is preferred to use. however, polymersprepared from monomer mixtures containing about 65 to 85 weight percentof styrene and 15 to weight percent of acrylonitrile. In any case thestyrene-acrylonitrile polymer should be a hard, tough, high-molecularweight thermoplastic material to obtain optimum results from its usewith the other components of the composition.

The styreneacrylonitrile polymers may be prepared by any of thepolymerization techniques known to and employed by those skilled in theart. Such methods as solu tion, suspension, emulsion and the like arepreferred. The form of the resin may be the solid dried product inpowder or granular form as a suspension, solution or emulsion, as willbe more fully described hereinafter. The amounts ofstyrene-acrylonitrile polymer employed in the compositions of thisinvention are from 1 to weight parts per 100 weight parts of polyvinylhalide. Better results are obtained when using 1 to 20 parts, and theconcentration is preferably from 1 to 10 parts per 100 weight parts ofthe vinyl halide polymer.

The rubbery interpolymers employed in the preparation of the polymercompositions of this invention contain a butadiene-l,3 hydrocarbon, anacrylonitrile and at least one other monoolefinic monomercopolymerizable with the butadiene-l,3 hydrocarbon and acrylonitrile.The interpolymers are prepared by polymerizing monomer mixturescontaining preferably 1,3-butadiene, acrylonitrile and one or more ofstyrene, chlorostyrenes, alkyl acrylates, alkyl methacrylates and likemonoolefinic co monomers. The monoolefinic comonomers which may becopolymerized with a butadiene-l,3 hydrocarbon and acrylonitrile arewell known to those skilled in the art and include such materials aspreferably styrene, dichlorostyrene and the like, and also include thealkyl acrylates such as ethyl acrylate, butyl acrylate, hexyl acrylate;alkyl methacrylates such as methyl methacrylate, butyl methacrylate.octyl methacrylate; vinyl alkyl ketones such as vinyl methyl l-tetone;vinyl alkyl ethers such as vinyl ethyl ether, vinyl pyridine, vinylnaphthalene and the like. in general the third monomeric constituent maybe a vinylidene compound containing the group CH2=C that is, containinga terminal methylene group attached by a double bond to a carbon atom.Other butadiene- 1,3 hydrocarbons such as isoprene, and otheracrylonitriles such as chloroacrylonitrile may also be employed. Theratio of the monomers by weight employed may be from about to 90 percentbutadiene-l,3 hydrocarbon, 5 to 30 weight percent of the acrylonitrile,and 5 to 30 weight percent of the other copolymerizable monoolefinicmonomers. It is preferred that only three component monomer mixtures bepolymerized for the rubbery inter polymers to be used in this invention,but small amounts of other copolymerizable monoolefinic monomers as setforth above may be present in the monomer mixture. Better results areobtained when the interpolymer used is prepared from monomer mixturescontaining from about to weight percent of 1,3-butadiene, from 10 to 20wei ht percent acrylonitrile, and 10 to 20 weight percent [0 anothermonoolefinic monomer copolymerizable with the butadienel,3 hydrocarbonand an acrylo nitrile selected from the group consisting of styrenes,alkyl acrylates and alkyl methacrylates. A more preferred in terpolymeris prepared from a monomer mixture containing 60 to 70 weight percentl,3-butadiene, 15 to 20 weight percent acrylonitrile and 15 to 20 weightpercent styrene. The polymer resulting from this monomer mixturecontributes the best balance of physical properties to the compositionsof this invention.

The rubbery interpolymers may be prepared by any of the polymerizationtechniques known to and employed by those skilled in the art, butemulsion polymerization is preferred. The interpolymer may be employedas the dry solid polymer, as a cement, dispersion, a latex and the like,and at any reasonable degree of conversion, although a conversionbetween 50 and percent is preferred. The interpolymer is preferablypolymerized to a Mooney value of about 25 to ML, and intcrpolymer with aMooney value of about 50 to 100 ML is more preferred. The interpolymerpreferably has a low gel content to obtain optimum results.

The amount of rubbery interpolyrner to be blended with the otheringredients to obtain the outstanding compositions of this invention maybe varied within rather broad limits, and one is still able to obtainuseful prod ucts; but if the advantages of the vinyl halide polymer areto be maintained, the amounts employed to obtain optimum results arerather critical. From 1 to 25 weight parts of interpolymer may be usedper 100 parts of vinyl halide polymer and styrene-acrylonitrile polymer.Better results are obtained if 5 to 15 parts are employed. andpreferably the amount is from about 10 weight parts per 100 weight partsof the other two constituents.

Unlike the composition described in the before-mentioned Jenningsapplication, the ingredients of this composition are not completelycompatible with each other. When combined in proper proportions, therubbery in gredient of the composition is not completely compatible withthe resinous ingredients, and it is this controlled incompatibilitywhich is believed to be responsible for the unexpected improvement inshock resistance obtained with very little loss of the initial physicalproperties of the resinous components. A butadicne-styrene eopolymer isnot compatible at all with the other two resinous materials, and thesmall degree of shock resistance that is obtained is at the expense ofthe other physical properties which are greatly degraded. in thecomposition of this invention, the three polymer constituents cooperateto contribute to the vastly improved impact strength and a good balanceof the other desirable physical properties and processability.

In the practice of this invention the ingredients may be mixed in anyorder and the ingredients may be in any conventional form. One preferredmethod is to blend the two compatible resins, the vinyl halide polymerand the styrene-acrylonitrile polymer, by mixing the dry resin powdersand then masticating with heating until a homogeneous sheet is formed.The two resinous components may also be blended in a Banbury mixer or ona plastic mill by first working one resin until a homogeneous sheet isformed, and then adding the other resin with further working unitlcomplete homogeneity is obtained. The intermixture of these twocomponents may then be blended with the rubbery interpolymer in aBanbury mixer or on a plastic mill by working the rubbery interpolymerinto the resinous blend. All three of the polymeric ingredients may beblended together in such mixing equipment and also by first dissolvingeach polymer in a mutual solvent, mixing the solutions and thenprecipitating the polymer blend from the mixed solutions or by takingoff the solvent as by evaporation. The separate polymer ingredients mayalso be prepared by polymerizing in the form of dispersions or emulsionsor suspensions, and then blending the suspensions or dispersions andcoagulating. These methods give particularly intimate mixtures of theingredients. Still another method is to polymerize the monomericingredients of one polymer, add to this the monomers of one of theothers, and successively continue the polymerization so as tooverpolymerize the second and third polymers on the particles of thefirst. The method employed to obtain the mixture of the threeingredients is not critical, the only requirement being that an intimatemixture of the three ingredients be obtained.

Regardless of the method by which the initial blending of the threepolymers is accomplished, it is generally preferred that the blendedpolymers be worked or masticated under heat and pressure to insureeificient dispersion of the various ingredients in the mixture. Thetemperature at which the mastication is conducted is not critical and isdependent to some extent on the thermoplastic character of the tworesins and the rubbery interpolymer. Unplasticized polyvinyl chloride isefficiently blended with a styrene-acrylonitrile copolymer bymastication at a temperature of about 300 F. The rubbery ingredient maybe incorporated into this mixture at this or a slightly lowertemperature. In general, temperatures of from about 200 to 400 F. arefound to be sutficient to accomplish efiicient mastication and mixing ofthe blended compositions containing the full range of useful andpermissible proportions of vinyl halide polymer, styrene-acrylonitrilepolymer, and the rubbery interpolymer.

For example, the two resins may be prepared as fine dry powders andmixed on a plastic mill with closelyset heated rolls at about 300 F. Theresins fuse after a few passes, and a sheet with a smooth-rolling bankis obtained. To this mixture is added the rubbery interpolymer. About 6passes are sufficient to obtain a good mixture. The resulting productmay be extruded in pipe sections which have very smooth surfaces. Theproduct may also be readily calendered to form very thin smooth sheetson a four-roll calender at about 350 F. The product may also be pressmolded, laminated, embossed, cut, drilled, machined and the like. Theresulting products are rigid, shock-resistant, have good low temperatureproperties, good resistance to heat distortion and an excellent balanceof stress-strain properties.

In the following examples will be found specific embodiments of theinvention and details employed in the practice of the invention. Thetests on all of the resulting samples are standard ASTM tests. All partsare parts by weight.

Examples 1 through IV 100 parts of high-molecular weight polyvinylchloride powder and 10 parts of a resin in powder form, which is made bypolymerizing in emulsion a monomer mixture containing 75 parts ofstyrene with parts of acrylonitrile, are intimately mixed and blended.100 parts of this resin mixture are placed in a dough-type mixer and 2parts of a tin mercaptide stabilizer added thereto. A rubberyinterpolymer having a Mooney value of 70 ML and prepared by polymerizinga monomer mixture of 67 parts of 1,3-butadiene, 16 parts ofacrylonitrile, and 17 parts of styrene in a fatty acid soap emulsion ata temperature of C. with potassium persulfate, is mixed with the resinmixture in four different proportions, 4, 6, 8 and 10 parts ofinterpolymer in separate batches with 110 parts of the resin mixture ineach case. The mixture of components is worked on a close-set two-rollplastic mill at about 300 F. The resulting product is sheeted off themill and molded in standard test molds for 5 minutes under pressure at345 F., the molds cooled and the If necessary, the samples are Thefollowing test molded stock removed. machined to the requiredtolerances. results are obtained on the samples:

When more than about 10 parts of the interploymer are employed, moremastication is ordinarily required than with lesser amounts. Thesecompositions process readily and may be formed into smooth-surfaced,tough, rigid, useful articles such as sheets, pipes and the like.

When Example IV is repeated with another rubbery interpolymer which isprepared by the emulsion polymerization of a monomer mixture of 67 partsof 1,3-butadiene, 16 parts of acrylonitrile and 17 parts of2,5-dichlorostyrene of a Mooney value of about ML, similar excellentresults are obtained, and the resulting polymer mixture has an Izodimpact value of about 9, tensile strength of about 6000 pounds persquare inch with an accompanying outstanding good balance of physicalproperties. Similarly, when an interpolymer containing methylmethacrylate instead of dichlorostyrene is employed, useful products areobtained.

When other rigid vinyl resins, other styrene-acrylonitrile polymers andother rubbery interpolymers of the types described are similarlyemployed, other useful products of high impact resistance which possessa good balance of other physical properties are obtained.

Other compounding ingredients such as extenders, stabilizers, colors andthe like may be employed in preparing the compositions of this inventionas is well known in the art so long as the balance between impactstrength, flexural strength, tensile strength, processability, heatdistortion and the like are not affected to such a degree that thecomposition is no longer useful as a tough, hard, rigid thermoplasticproduct.

While we have disclosed certain preferred embodiments of the inventionin the examples, we do not thereby desire or intend to limit theinvention solely thereto, for as has been disclosed, the materials,proportions and methods may be varied within wide limits, andequivalents may be employed without departing from the scope and spiritof the invention as defined in the appended claims, and it is to theseonly that we intend to limit the invention.

We claim:

1. An improved, shock-resistant, processable, rigid, thermoplasticcomposition comprising an intimate mixture of (1) a rigid vinyl halidepolymer of a monomeric material comprised predominately of a vinylhalide and lesser amounts of other monoolefinic monomers, (2) a hard,tough, resinous polymer of a predominately monoolefinic mixturecomprising 50 to weight percent of a monomer selected from the classconsisting of styrene, alkyl styrenes, and chlorostyrenes and 10 to 50weight percent of a monomer selected from the class consisting ofacrylonitrile, methacrylonitrile and chloroacrylonitrile and (3) arubbery interpolymer of a monomer mixture comprising 50 to 90 weightpercent of a l,3-butadiene hydrocarbon, 5 to 30 weight percent of anacrylonitrile and 5 to 30 weight percent of at least one othermonoolefinic monomer copolymerizable with the 1,3-butadiene hydrocarbonand acrylonitrile, said thermoplastic polymeric composition containingessentially from 1 to 40 weight parts of (2) based on weight parts of(l) and 1 to 25 weight parts of (3) based on 100 weight parts of (l) and(2).

2. The composition of claim 1 wherein 1) is polyvinyl chloride.

3. The improved, shock-resistant, processable, rigid, thermoplasticcomposition of claim 1 wherein (1) is comprised predominately ofchloride with lesser amounts of other polymerized monoolefinic monomers,(2) is a copolymer of 60 to 90 weight percent of styrene and 10 to 40weight percent of acrylonitrile and (3) is a rubbery interpolymercomprising 50 to 90 weight percent of 1,3- butadiene, 5 to 30 weightpercent of acrylonitrile and 5 to 30 weight percent of a comonomerselected from the class consisting of. styrene, alkyl acrylates andalkyl methacrylates, and the said composition contains essentially from1 to 20 weight parts of (2) based on 100 weight parts of (l) and from 5to 15 weight parts of (3) based on 100 weight parts of (1) and (2).

4. The improved, shock-resistant, processable, rigid, thermoplasticcomposition of claim 3 wherein (l) is a hard, tough, high-molecularweight polyvinyl chloride.

(2) is a styreneacrylonitrile copolymer containing 65 to v 85 weightpercent of styrene and 15 to 35 weight percent of acrylonitrile, and (3)is a rubbery interpolymer prepared from a monomer mixture containing 65to 70 weight percent of 1,3-butadiene, 15 to 20 weight percent ofacrylonitrile and 15 to 20 weight per-cent of styrene, said compositioncontaining from 1 to weight parts of (2) based on 100 weight parts of(1) and 5 to weight parts of (3) based on 100 weight parts of (1) and(2).

5. The improved, shock-resistant, processable, rigid, thermoplasticcomposition of claim 3 wherein (1) is a hard, tough, high-molecularweight polyvinyl chloride, (2) is a styreneacrylonitrile copolymercontaining 65 to 85 weight percent of styrene and 15 to 35 weightpercent of acrylonitrile, and (3) is a rubbery interpolymer preparedfrom a monomer mixture containing 65 to 70 weight percent of1,3-butadiene, 15 to weight percent of acrylonitrile and 15 to 20 weightpercent of a chlorostyrene, said composition containing from 1 to 10weight parts of (2) based on 100 weight parts of (1) and 5 to 15 weightparts of (3) based on 100 weight parts of (l) and (2).

6. The improved, shock-resistant, processable, rigid, thermoplasticcomposition of claim 3 wherein (1) is a hard, tough, high-molecularweight polyvinyl chloride, (2) is a styreneacrylonitrile copolymercontaining 65 to 85 weight percent of styrene and 15 to weight percentof acrylonitrile, and (3) is a rubbery interpolymer prepared from amonomer mixture containing 65 to 70 weight percent of 1,3-butadiene, 15to 20 weight percent of acrylonitrile and 15 to 20 weight percent of analkyl methacrylzite, said composition containing from 1 to 10 weightparts of (2) based on 100 weight parts of (l) and 5 to 15 weight partsof (3) based on 100 weight parts of (1) and (2).

7. The improved, shock-resistant, processable, rigid, thermoplasticcomposition of claim 3 wherein (l) is a hard, tough, high-molecularweight polyvinyl chloride, (2) is a copolymer of 65 to 85 weight percentof methyl styrene and 15 to 35 weight percent of acrylonitrile, and 3)is a rubbery interpolymer prepared from a monomer mixture containing 65to 70 weight percent of 1,3-butadienc, 15 to 20 weight percent ofacrylonitrile and 15 to 20 weight percent of styrene, said compositioncontaining from 1 to 10 weight parts of (2) based on 100 weight parts of(1) and 5 to 15 weight parts of (3) based on 100 weight parts of (1) and(2).

8. The method of improving the shock-resistance of a normally hard,tough and horny vinyl halide polymer of a monomer mixture comprisedpredominately of a vinyl halide and lesser amounts of other monoolefinicmonomers, which method comprises mixing with 100 weight parts of thesaid vinyl halide polymer (1) 1 to weight parts of a hard, tough,resinous polymer of a predominately monoolefinic mixture comprising to90 weight percent of a monomer selected from the class consisting ofstyrene, alkyl styrenes, and chlorostyrenes and 10 to 50 weight percentof a monomer selected from the class consisting of acrylonitrile,methacrylonitrile and chloroacrylonitrile and (2) 1 to 25 weight partsof a rubbery interpolymer of a polymerized mixture comprising 50 to 90weight percent of a 1,3-butadiene hydrocarbon, 5 to 30 weight percent ofan acrylonitrile and 5 to 30 weight percent of at least one othercopolymerizable monoolefinic monomer in an amount 1 to 25 weight partsbased on 100 weight parts of the two resinous components, and thenmasticating the polymer mixture while heating at a temperature fromabout 200 F. to about 400 F. to effect an intimate mixture of thepolymeric materials.

9. An improved, shock-resistant, processable, rigid thermoplasticcomposition comprising an intimate mixture of (1) polyvinyl chloride,(2) a resinous copolymer containing about 75 weight percent styrene andabout 25 weight percent acrylonitrile and 3) a rubbery interpolymerprepared from a monomer mixture containing about to weight percent1,3-butadiene, about 10 to 20 weight percent acrylonitrile and about 10to 20 weight percent styrene, said composition containing from about 1to about 10 weight parts of (2) based on 100 weight parts of (1) andabout 5 to about 15 weight parts of (3) based on 100 weight parts of (1)and (2).

10. An improved, shock-resistant, processable, rigid, thermoplasticcomposition comprising an intimate mixture of (1) polyvinyl chloride,(2) a copolymer of 50 to weight percent styrene and 50 to 10 weightpercent acrylonitrile and (3) a rubbery interpolymer of a monomermixture comprising 50 to 90 weight percent of 1,3- butadiene, 5 to 30weight percent of acrylonitrile and 5 to 30 weight percent of at leastone other monoolefinic \nonomer copolymerizable with the 1,3-butadieneand acrylonitrile, said thermoplastic composition containing essentiallyfrom 1 to 40 weight parts of (2) based on weight parts of (1) and from 1to 25 weight parts of (3) based on 100 weight parts of (1) and (2).

References Cited in the file of this patent UNITED STATES PATENTS2,330,353 Henderson Sept. 28, 1943 2,439,202 Daly Apr. 6, 1948 2,550,139Daly April 24, 1951 2,646,417 Jennings July 21, 1953 2,652,384 Sayko etal. Sept. 15, 1953 2,713,566 Reid July 15, 1955 FOREIGN PATENTS 947,162France Ian. 3, 1949

1. AN IMPROVED, SHOCK-RESISTANT, PROCESSABLE, RIGID, THERMOPLASTICCOMPOSITION COMPRISING AN INTIMATE MIXTURE OF (1) A RIGID VINYL HALIDEPOLYMER OF A MONOMERIC MATERIAL COMPRISED PREDOMINATELY OF A VINLYHALIDE AND LESSER AMOUNTS OF OTHER MONOOLEFINEC MONOMERS, (2) A HARD,TOUGH, RESINOUS POLYMER OF A PREDOMINATELY MON0OLEFINIC MIXTURECOMPRISING 50 TO 90 WEIGHT PERCENT OF A MONOMER SELECTED FROM THE CLASSCONSISTING OF STYRENE, ALKYL STYRENES, AND CLOROSTYRENES AND 10 TO 50WEIGHT PERCENT OF A MONOMER SELECTED FROM THE CLASS CONSISTING OFACRYLONITRILE, METHACRYLONITRILE AND CHLOROACRYLONITRILE AND (3) ARUBBERY INTERPOLYMER OF A MONOMER MIXTURE COMPRISING 50 TO 90 WEIGHTPERCENT OF A 1,3-BUTADIENE HYDROCARBON, 5 TO 30 WEIGHT PERCENTOF ANACRYLONITRILE AND 5 TO30 WEIGHT PERCENT OF AT LEAST ONE OTHERMONOOLEFINIC MONOMER COPOLYMERIZABLE WITH THE 1,3-BUTADIENE HYDROCARBONAND ACRYLONITRILE, SAID THERMOPLASTIC POLYMERIC COMPOSITION CONTAININGESSENTIALLY FROM 1 TO 40 WEIGHT PARTS OF (2) BASED ON 100 WEIGHT PARTSOF (1) AND 1 TO 25 WEIGHT PARTS OF (3) BASED ON 100 WEIGHT PARTS OF (1)AND (2).